title: Separate and combined associations of body-mass index and abdominal adiposity with cardiovascular disease: collaborative analysis of 58 prospective studies.
abstract: BACKGROUND
  Guidelines differ about the value of assessment of adiposity measures for cardiovascular disease risk prediction when information is available for other risk factors. We studied the separate and combined associations of body-mass index (BMI), waist circumference, and waist-to-hip ratio with risk of first-onset cardiovascular disease.
  
  
  METHODS
  We used individual records from 58 cohorts to calculate hazard ratios (HRs) per 1 SD higher baseline values (4.56 kg/m(2) higher BMI, 12.6 cm higher waist circumference, and 0.083 higher waist-to-hip ratio) and measures of risk discrimination and reclassification. Serial adiposity assessments were used to calculate regression dilution ratios.
  
  
  RESULTS
  Individual records were available for 221,934 people in 17 countries (14,297 incident cardiovascular disease outcomes; 1.87 million person-years at risk). Serial adiposity assessments were made in up to 63,821 people (mean interval 5.7 years [SD 3.9]). In people with BMI of 20 kg/m(2) or higher, HRs for cardiovascular disease were 1.23 (95% CI 1.17-1.29) with BMI, 1.27 (1.20-1.33) with waist circumference, and 1.25 (1.19-1.31) with waist-to-hip ratio, after adjustment for age, sex, and smoking status. After further adjustment for baseline systolic blood pressure, history of diabetes, and total and HDL cholesterol, corresponding HRs were 1.07 (1.03-1.11) with BMI, 1.10 (1.05-1.14) with waist circumference, and 1.12 (1.08-1.15) with waist-to-hip ratio. Addition of information on BMI, waist circumference, or waist-to-hip ratio to a cardiovascular disease risk prediction model containing conventional risk factors did not importantly improve risk discrimination (C-index changes of -0.0001, -0.0001, and 0.0008, respectively), nor classification of participants to categories of predicted 10-year risk (net reclassification improvement -0.19%, -0.05%, and -0.05%, respectively). Findings were similar when adiposity measures were considered in combination. Reproducibility was greater for BMI (regression dilution ratio 0.95, 95% CI 0.93-0.97) than for waist circumference (0.86, 0.83-0.89) or waist-to-hip ratio (0.63, 0.57-0.70).
  
  
  CONCLUSIONS
  BMI, waist circumference, and waist-to-hip ratio, whether assessed singly or in combination, do not importantly improve cardiovascular disease risk prediction in people in developed countries when additional information is available for systolic blood pressure, history of diabetes, and lipids.
  
  
  BACKGROUND
  British Heart Foundation and UK Medical Research Council.
authors.affiliation: Emerging Risk Factors Collaboration Coordinating Centre, Department of Public Health and Primary Care, University of Cambridge, Strangeways Research Laboratory, Cambridge CB1 8RN, UK. erfc@phpc.cam.ac.uk
authors.forename: David
authors.initials: D
authors.lastname: Wormser
authors.forename: Stephen
authors.initials: S
authors.lastname: Kaptoge
authors.forename: Emanuele
authors.initials: E
authors.lastname: Di Angelantonio
authors.forename: Angela M
authors.initials: AM
authors.lastname: Wood
authors.forename: Lisa
authors.initials: L
authors.lastname: Pennells
authors.forename: Alex
authors.initials: A
authors.lastname: Thompson
authors.forename: Nadeem
authors.initials: N
authors.lastname: Sarwar
authors.forename: Jorge R
authors.initials: JR
authors.lastname: Kizer
authors.forename: Debbie A
authors.initials: DA
authors.lastname: Lawlor
authors.forename: Børge G
authors.initials: BG
authors.lastname: Nordestgaard
authors.forename: Paul
authors.initials: P
authors.lastname: Ridker
authors.forename: Veikko
authors.initials: V
authors.lastname: Salomaa
authors.forename: June
authors.initials: J
authors.lastname: Stevens
authors.forename: Mark
authors.initials: M
authors.lastname: Woodward
authors.forename: Naveed
authors.initials: N
authors.lastname: Sattar
authors.forename: Rory
authors.initials: R
authors.lastname: Collins
authors.forename: Simon G
authors.initials: SG
authors.lastname: Thompson
authors.forename: Gary
authors.initials: G
authors.lastname: Whitlock
authors.forename: John
authors.initials: J
authors.lastname: Danesh
mesh_terms: D000367:Age Factors; D001794:Blood Pressure; D015992:Body Mass Index; D002318:Cardiovascular Diseases / Q000453:epidemiology*; D002784:Cholesterol / Q000097:blood; D008076:Cholesterol, HDL / Q000097:blood; D003920:Diabetes Mellitus / Q000453:epidemiology; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D056128:Obesity, Abdominal / Q000453:epidemiology*; D016016:Proportional Hazards Models; D011446:Prospective Studies; D018570:Risk Assessment; D012737:Sex Factors; D012907:Smoking / Q000453:epidemiology; D013599:Systole; D055105:Waist Circumference; D049629:Waist-Hip Ratio
chemical_list: D008076:Cholesterol, HDL; D002784:Cholesterol